Shift of the 21+^+_1 state of 10^{10}Be in the ternary cold fission of 252^{252}Cf

Recent experimental data indicate that in the ternary cold fission of $^{252}$Cf the energy of the first excited state of the accompanying light cluster $^{10}$Be is decreased by an amount ranging between $\approx$ 6 and 26 keV. A model is proposed to calculate the shift of the vibrational 2$^+_1$ state in $^{10}$Be when its heavy companions are the even-even nuclei $^{146}$Ba and $^{96}$Sr. The stiffness parameters of the $\beta$-vibrations are calculated within the self-consistent Hartree-Fock method with BCS pairing correlations taken into account, and its change is determined by the interaction of the light cluster with the heavy fragments. The results are pointing to a dependence of the shift magnitude and signature on the relative distance between the three clusters and their mutual orientation. Eventually it is the anharmonic perturbation of the spherical vibrator which is responsible for obtaining a negative energy shift of the 2$^+_1$ state.Comment: 4 pages, 3 figure

Predictive coupled-cluster isomer orderings for some Sin{}_nCm{}_m (m,n≤12m, n\le 12) clusters; A pragmatic comparison between DFT and complete basis limit coupled-cluster benchmarks

The accurate determination of the preferred ${\rm Si}_{12}{\rm C}_{12}$ isomer is important to guide experimental efforts directed towards synthesizing SiC nano-wires and related polymer structures which are anticipated to be highly efficient exciton materials for opto-electronic devices. In order to definitively identify preferred isomeric structures for silicon carbon nano-clusters, highly accurate geometries, energies and harmonic zero point energies have been computed using coupled-cluster theory with systematic extrapolation to the complete basis limit for set of silicon carbon clusters ranging in size from SiC$_3$ to ${\rm Si}_{12}{\rm C}_{12}$. It is found that post-MBPT(2) correlation energy plays a significant role in obtaining converged relative isomer energies, suggesting that predictions using low rung density functional methods will not have adequate accuracy. Utilizing the best composite coupled-cluster energy that is still computationally feasible, entailing a 3-4 SCF and CCSD extrapolation with triple-$\zeta$ (T) correlation, the {\it closo} ${\rm Si}_{12}{\rm C}_{12}$ isomer is identified to be the preferred isomer in support of previous calculations [J. Chem. Phys. 2015, 142, 034303]. Additionally we have investigated more pragmatic approaches to obtaining accurate silicon carbide isomer energies, including the use of frozen natural orbital coupled-cluster theory and several rungs of standard and double-hybrid density functional theory. Frozen natural orbitals as a way to compute post MBPT(2) correlation energy is found to be an excellent balance between efficiency and accuracy

Contribution of Matrix Metalloproteinase-9 to Cerebral Edema and Functional Outcome following Experimental Subarachnoid Hemorrhage

Background: Cerebral edema is an important risk factor for death and poor outcome following subarachnoid hemorrhage (SAH). However, underlying mechanisms are still poorly understood. Matrix metalloproteinase (MMP)-9 is held responsible for the degradation of microvascular basal lamina proteins leading to blood-brain barrier dysfunction and, thus, formation of vasogenic cerebral edema. The current study was conducted to clarify the role of MMP-9 for the development of cerebral edema and for functional outcome after SAH. Methods: SAH was induced in FVB/N wild-type (WT) or MMP-9 knockout (MMP-9(-/-)) mice by endovascular puncture. Intracranial pressure (ICP), regional cerebral blood flow (rCBF), and mean arterial blood pressure (MABP) were continuously monitored up to 30 min after SAH. Mortality was quantified for 7 days after SAH. In an additional series neurological function and body weight were assessed for 3 days after SAH. Subsequently, ICP and brain water content were quantified. Results: Acute ICP, rCBF, and MABP did not differ between WT and MMP-9(-/-) mice, while 7 days' mortality was lower in MMP-9(-/-) mice (p = 0.03; 20 vs. 60%). MMP-9(-/-) mice also exhibited better neurological recovery, less brain edema formation, and lower chronic ICP. Conclusions: The results of the current study suggest that MMP-9 contributes to the development of early brain damage after SAH by promoting cerebral edema formation. Hence, MMP-9 may represent a novel molecular target for the treatment of SAH. Copyright (C) 2011 S. Karger AG, Base

On the nature of candidate luminous blue variables in M33

Luminous blue variables (LBVs) are expected to play an important role in massive stellar evolution as well as being the progenitors of some of the most luminous supernovae known. In this paper we provide a multiwavelength study of the population of (candidate) LBVs identified within M33. New spectra provide an observational baseline of >4yr with respect to published data, which is well suited to identifying LBV outbursts. Multi-epoch optical and mid-IR surveys of M33 further constrain the variability of the sample and permit a search for dusty circumstellar ejecta. Spectroscopic and photometric variability appears common amongst the sample, although in many cases further observations will be required to determine its physical origin. Nevertheless, we report a new outburst of M33 Var C, while the transition of the WNLh star B517 to a cooler B supergiant phase between 1993-2010 confirms an LBV classification. Proof-of-concept quantitative analysis is provided for Romano's star; the results being consistent with the finding that its bolometric luminosity varies during its LBV excursions. The combination of the temperature and luminosity of two stars, the B hypergiant [HS80] 110A and the cool hypergiant B324, appears to be in violation of the empirical Humphreys-Davidson limit. Mid-IR observations demonstrate that a number of candidates appear associated with hot circumstellar dust, although no objects as extreme as Eta Carinae are identified. The combined multiwavelength dataset suggests that the population of LBVs studied is contaminated by stars demonstrating the B[e] phenomenon. Of these, a subset of optically faint, low luminosity stars associated with hot dust are of particular interest since they appear similar to the likely progenitors of SN 2008S and the 2008 NGC300 transient, albeit suffering less intrinsic extinction. [ABRIDGED]Comment: 23 pages, 14 figures, accepted for publication in Astronomy and Astrophysic

Charge Delocalization in Self-Assembled Mixed-Valence Aromatic Cation Radicals

The spontaneous assembly of aromatic cation radicals (D+•) with their neutral counterpart (D) affords dimer cation radicals (D2+•). The intermolecular dimeric cation radicals are readily characterized by the appearance of an intervalence charge-resonance transition in the NIR region of their electronic spectra and by ESR spectroscopy. The X-ray crystal structure analysis and DFT calculations of a representative dimer cation radical (i.e., the octamethylbiphenylene dimer cation radical) have established that a hole (or single positive charge) is completely delocalized over both aromatic moieties. The energetics and the geometrical considerations for the formation of dimer cation radicals is deliberated with the aid of a series of cyclophane-like bichromophoric donors with drastically varied interplanar angles between the cofacially arranged aryl moieties. X-ray crystallography of a number of mixed-valence cation radicals derived from monochromophoric benzenoid donors established that they generally assemble in 1D stacks in the solid state. However, the use of polychromophoric intervalence cation radicals, where a single charge is effectively delocalized among all of the chromophores, can lead to higher-order assemblies with potential applications in long-range charge transport. As a proof of concept, we show that a single charge in the cation radical of a triptycene derivative is evenly distributed on all three benzenoid rings and this triptycene cation radical forms a 2D electronically coupled assembly, as established by X-ray crystallography

Strengthening regulatory science in academia:STARS, an EU initiative to bridge the translational gap

Truly disruptive medicine innovation and new treatment paradigms tend to start in non-commercial research institutions. However, the lack of mutual understanding between medicine developers and regulators when it comes to medicine development significantly delays or even prevents the access of patients to these innovations. Here, we outline what regulatory-related barriers hamper the translational development of novel products or new treatment paradigms initiated in academia, and propose key steps towards improved regulatory dialogue among academia, funding bodies and regulatory authorities. Moreover, we briefly describe how the STARS (Strengthening Training of Academia in Regulatory Science) project aims to reach out to medicine innovators in academia to bridge the regulatory knowledge gap and enhance this dialogue to facilitate the implementation of academic research findings in clinical practice

Valence and Charge-transfer Optical Properties for Some Si\u3csub\u3en\u3c/sub\u3eC\u3csub\u3em\u3c/sub\u3e (m, n ≤ 12) Clusters: Comparing TD-DFT, Complete-basis-limit EOMCC, and Benchmarks from Spectroscopy

Accurate optical characterization of the closo-Si12C12 molecule is important to guide experimental efforts toward the synthesis of nano-wires, cyclic nano-arrays, and related array structures, which are anticipated to be robust and efficient exciton materials for opto-electronic devices. Working toward calibrated methods for the description of closo-Si12C12 oligomers, various electronic structure approaches are evaluated for their ability to reproduce measured optical transitions of the SiC2, Si2Cn (n = 1–3), and Si3Cn (n = 1, 2) clusters reported earlier by Steglich and Maier [Astrophys. J. 801, 119 (2015)]. Complete-basis-limit equation-of-motion coupled-cluster (EOMCC) results are presented and a comparison is made between perturbative and renormalized non-iterative triples corrections. The effect of adding a renormalized correction for quadruples is also tested. Benchmark test sets derived from both measurement and high-level EOMCC calculations are then used to evaluate the performance of a variety of density functionals within the time-dependent density functional theory (TD-DFT) framework. The best-performing functionals are subsequently applied to predict valence TD-DFT excitation energies for the lowest-energy isomers of SinC and Sin−1C7−n (n = 4–6). TD-DFT approaches are then applied to the SinCn (n = 4–12) clusters and unique spectroscopic signatures of closo-Si12C12 are discussed. Finally, various long-range corrected density functionals, including those from the CAM-QTP family, are applied to a charge-transfer excitation in a cyclic (Si4C4)4 oligomer. Approaches for gauging the extent of charge-transfer character are also tested and EOMCC results are used to benchmark functionals and make recommendations

Dendrite growth in undercooled Al-rich Al-Ni melts measured on Earth and in Space

The dendrite growth velocity in Al₇₅Ni₂₅ melts has been measured in a containerless procedure as a function of undercooling using an electromagnetic levitation technique both in the Earth laboratory and in Space on board the International Space Station. The growth shows an anomalous behavior inasmuch as the growth velocity decreases with increasing undercooling, confirming previous experiments on Earth. Within the scatter of experimental data, results obtained on Earth and in Space do not show significant differences. Thus, convection effects as the origin of the anomalous growth characteristics can be excluded. However, high-speed video recording exhibits multiple nucleation events in front of the growing solid-liquid interface. This effect is identified as the origin of the anomalous dendrite growth characteristics in undercooled melts of Al-rich Al-Ni melts